Rearrangements of bicyclic monoterpenes
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
The stereochemistry of reaction of phenylmagnesium bromide with camphor (43) has been determined. The attempted preparation of the phenyl alcohol (46) by oxymercuration of 2-phenylbornylene (72) resulted in the formation of the vinyl-mercury (81). Consequently the oxymercuration of a number of olefins was carried out to determine the vital structural features for the occurrence of vinylmercury compound formation. Attempted preparation of epoxides (49 and 50) by m-chloroperbenzoic acid oxidation of the olefin (72) gave largely 2-endo-phenyl ketone (87). An attempt to prepare the bromohydrin (90) by reaction with aqueous N-bromosuccinimide resulted in formation of the bromo-olefin (70). The exo- and endo-epoxides (49 and 50) were prepared by a novel syn-elimination reaction of the two cis-diol monotosylates (60 and 93). The acid catalysed rearrangement of the endo-epoxide (50) gave only the 2-endo-phenyl ketone (87), while the exo-epoxide (49) gave mainly the aldehyde (119). The cyclic sulphites (95a and 95b) were prepared from the cis-exo-diol (59) obtained by potassium permanganate oxidation of the olefin (72). Thermal rearrangement of the cyclic sulphites gave the aldehyde (119) and the 2-endo-pbenyl ketone (87). The greater proportion of the ketone (87) from the anti-cyclic sulphite (95a) has been rationalised in terms of the stereochemistry about the sulphur atom. A study of the thermal rearrangements of the 2,3-butane epoxides (108 and 109) with sulphur dioxide and the cyclic sulphites (116 and 117) is described.